1 /* 2 * Copyright (c) 1988 Stephen Deering. 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Stephen Deering of Stanford University. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)igmp.c 8.1 (Berkeley) 7/19/93 34 * $FreeBSD$ 35 */ 36 37 /* 38 * Internet Group Management Protocol (IGMP) routines. 39 * 40 * Written by Steve Deering, Stanford, May 1988. 41 * Modified by Rosen Sharma, Stanford, Aug 1994. 42 * Modified by Bill Fenner, Xerox PARC, Feb 1995. 43 * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. 44 * 45 * MULTICAST Revision: 3.5.1.4 46 */ 47 48 #include "opt_mac.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/mac.h> 53 #include <sys/malloc.h> 54 #include <sys/mbuf.h> 55 #include <sys/socket.h> 56 #include <sys/protosw.h> 57 #include <sys/kernel.h> 58 #include <sys/sysctl.h> 59 60 #include <net/if.h> 61 #include <net/route.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_var.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 #include <netinet/ip_var.h> 68 #include <netinet/igmp.h> 69 #include <netinet/igmp_var.h> 70 71 #include <machine/in_cksum.h> 72 73 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 74 75 static struct router_info *find_rti(struct ifnet *ifp); 76 static void igmp_sendpkt(struct in_multi *, int, unsigned long); 77 78 static struct igmpstat igmpstat; 79 80 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat, 81 igmpstat, ""); 82 83 static SLIST_HEAD(, router_info) router_info_head; 84 static int igmp_timers_are_running; 85 static u_long igmp_all_hosts_group; 86 static u_long igmp_all_rtrs_group; 87 static struct mbuf *router_alert; 88 static struct route igmprt; 89 90 #ifdef IGMP_DEBUG 91 #define IGMP_PRINTF(x) printf(x) 92 #else 93 #define IGMP_PRINTF(x) 94 #endif 95 96 void 97 igmp_init(void) 98 { 99 struct ipoption *ra; 100 101 /* 102 * To avoid byte-swapping the same value over and over again. 103 */ 104 igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 105 igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 106 107 igmp_timers_are_running = 0; 108 109 /* 110 * Construct a Router Alert option to use in outgoing packets 111 */ 112 MGET(router_alert, M_DONTWAIT, MT_DATA); 113 ra = mtod(router_alert, struct ipoption *); 114 ra->ipopt_dst.s_addr = 0; 115 ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 116 ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 117 ra->ipopt_list[2] = 0x00; 118 ra->ipopt_list[3] = 0x00; 119 router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 120 121 SLIST_INIT(&router_info_head); 122 } 123 124 static struct router_info * 125 find_rti(struct ifnet *ifp) 126 { 127 struct router_info *rti; 128 129 IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); 130 SLIST_FOREACH(rti, &router_info_head, rti_list) { 131 if (rti->rti_ifp == ifp) { 132 IGMP_PRINTF( 133 "[igmp.c, _find_rti] --> found old entry \n"); 134 return rti; 135 } 136 } 137 MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 138 rti->rti_ifp = ifp; 139 rti->rti_type = IGMP_V2_ROUTER; 140 rti->rti_time = 0; 141 SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); 142 143 IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 144 return rti; 145 } 146 147 void 148 igmp_input(register struct mbuf *m, int off) 149 { 150 register int iphlen = off; 151 register struct igmp *igmp; 152 register struct ip *ip; 153 register int igmplen; 154 register struct ifnet *ifp = m->m_pkthdr.rcvif; 155 register int minlen; 156 register struct in_multi *inm; 157 register struct in_ifaddr *ia; 158 struct in_multistep step; 159 struct router_info *rti; 160 int timer; /** timer value in the igmp query header **/ 161 162 ++igmpstat.igps_rcv_total; 163 164 ip = mtod(m, struct ip *); 165 igmplen = ip->ip_len; 166 167 /* 168 * Validate lengths 169 */ 170 if (igmplen < IGMP_MINLEN) { 171 ++igmpstat.igps_rcv_tooshort; 172 m_freem(m); 173 return; 174 } 175 minlen = iphlen + IGMP_MINLEN; 176 if ((m->m_flags & M_EXT || m->m_len < minlen) && 177 (m = m_pullup(m, minlen)) == 0) { 178 ++igmpstat.igps_rcv_tooshort; 179 return; 180 } 181 182 /* 183 * Validate checksum 184 */ 185 m->m_data += iphlen; 186 m->m_len -= iphlen; 187 igmp = mtod(m, struct igmp *); 188 if (in_cksum(m, igmplen)) { 189 ++igmpstat.igps_rcv_badsum; 190 m_freem(m); 191 return; 192 } 193 m->m_data -= iphlen; 194 m->m_len += iphlen; 195 196 ip = mtod(m, struct ip *); 197 timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 198 if (timer == 0) 199 timer = 1; 200 rti = find_rti(ifp); 201 202 /* 203 * In the IGMPv2 specification, there are 3 states and a flag. 204 * 205 * In Non-Member state, we simply don't have a membership record. 206 * In Delaying Member state, our timer is running (inm->inm_timer) 207 * In Idle Member state, our timer is not running (inm->inm_timer==0) 208 * 209 * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 210 * we have heard a report from another member, or IGMP_IREPORTEDLAST 211 * if I sent the last report. 212 */ 213 switch (igmp->igmp_type) { 214 case IGMP_MEMBERSHIP_QUERY: 215 ++igmpstat.igps_rcv_queries; 216 217 if (ifp->if_flags & IFF_LOOPBACK) 218 break; 219 220 if (igmp->igmp_code == 0) { 221 /* 222 * Old router. Remember that the querier on this 223 * interface is old, and set the timer to the 224 * value in RFC 1112. 225 */ 226 227 rti->rti_type = IGMP_V1_ROUTER; 228 rti->rti_time = 0; 229 230 timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 231 232 if (ip->ip_dst.s_addr != igmp_all_hosts_group || 233 igmp->igmp_group.s_addr != 0) { 234 ++igmpstat.igps_rcv_badqueries; 235 m_freem(m); 236 return; 237 } 238 } else { 239 /* 240 * New router. Simply do the new validity check. 241 */ 242 243 if (igmp->igmp_group.s_addr != 0 && 244 !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 245 ++igmpstat.igps_rcv_badqueries; 246 m_freem(m); 247 return; 248 } 249 } 250 251 /* 252 * - Start the timers in all of our membership records 253 * that the query applies to for the interface on 254 * which the query arrived excl. those that belong 255 * to the "all-hosts" group (224.0.0.1). 256 * - Restart any timer that is already running but has 257 * a value longer than the requested timeout. 258 * - Use the value specified in the query message as 259 * the maximum timeout. 260 */ 261 IN_FIRST_MULTI(step, inm); 262 while (inm != NULL) { 263 if (inm->inm_ifp == ifp && 264 inm->inm_addr.s_addr != igmp_all_hosts_group && 265 (igmp->igmp_group.s_addr == 0 || 266 igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 267 if (inm->inm_timer == 0 || 268 inm->inm_timer > timer) { 269 inm->inm_timer = 270 IGMP_RANDOM_DELAY(timer); 271 igmp_timers_are_running = 1; 272 } 273 } 274 IN_NEXT_MULTI(step, inm); 275 } 276 277 break; 278 279 case IGMP_V1_MEMBERSHIP_REPORT: 280 case IGMP_V2_MEMBERSHIP_REPORT: 281 /* 282 * For fast leave to work, we have to know that we are the 283 * last person to send a report for this group. Reports 284 * can potentially get looped back if we are a multicast 285 * router, so discard reports sourced by me. 286 */ 287 IFP_TO_IA(ifp, ia); 288 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 289 break; 290 291 ++igmpstat.igps_rcv_reports; 292 293 if (ifp->if_flags & IFF_LOOPBACK) 294 break; 295 296 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 297 ++igmpstat.igps_rcv_badreports; 298 m_freem(m); 299 return; 300 } 301 302 /* 303 * KLUDGE: if the IP source address of the report has an 304 * unspecified (i.e., zero) subnet number, as is allowed for 305 * a booting host, replace it with the correct subnet number 306 * so that a process-level multicast routing daemon can 307 * determine which subnet it arrived from. This is necessary 308 * to compensate for the lack of any way for a process to 309 * determine the arrival interface of an incoming packet. 310 */ 311 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 312 if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 313 314 /* 315 * If we belong to the group being reported, stop 316 * our timer for that group. 317 */ 318 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 319 320 if (inm != NULL) { 321 inm->inm_timer = 0; 322 ++igmpstat.igps_rcv_ourreports; 323 324 inm->inm_state = IGMP_OTHERMEMBER; 325 } 326 327 break; 328 } 329 330 /* 331 * Pass all valid IGMP packets up to any process(es) listening 332 * on a raw IGMP socket. 333 */ 334 rip_input(m, off); 335 } 336 337 void 338 igmp_joingroup(struct in_multi *inm) 339 { 340 int s = splnet(); 341 342 if (inm->inm_addr.s_addr == igmp_all_hosts_group 343 || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 344 inm->inm_timer = 0; 345 inm->inm_state = IGMP_OTHERMEMBER; 346 } else { 347 inm->inm_rti = find_rti(inm->inm_ifp); 348 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 349 inm->inm_timer = IGMP_RANDOM_DELAY( 350 IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 351 inm->inm_state = IGMP_IREPORTEDLAST; 352 igmp_timers_are_running = 1; 353 } 354 splx(s); 355 } 356 357 void 358 igmp_leavegroup(struct in_multi *inm) 359 { 360 361 if (inm->inm_state == IGMP_IREPORTEDLAST && 362 inm->inm_addr.s_addr != igmp_all_hosts_group && 363 !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 364 inm->inm_rti->rti_type != IGMP_V1_ROUTER) 365 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 366 } 367 368 void 369 igmp_fasttimo(void) 370 { 371 register struct in_multi *inm; 372 struct in_multistep step; 373 int s; 374 375 /* 376 * Quick check to see if any work needs to be done, in order 377 * to minimize the overhead of fasttimo processing. 378 */ 379 380 if (!igmp_timers_are_running) 381 return; 382 383 s = splnet(); 384 igmp_timers_are_running = 0; 385 IN_FIRST_MULTI(step, inm); 386 while (inm != NULL) { 387 if (inm->inm_timer == 0) { 388 /* do nothing */ 389 } else if (--inm->inm_timer == 0) { 390 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 391 inm->inm_state = IGMP_IREPORTEDLAST; 392 } else { 393 igmp_timers_are_running = 1; 394 } 395 IN_NEXT_MULTI(step, inm); 396 } 397 splx(s); 398 } 399 400 void 401 igmp_slowtimo(void) 402 { 403 int s = splnet(); 404 struct router_info *rti; 405 406 IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 407 SLIST_FOREACH(rti, &router_info_head, rti_list) { 408 if (rti->rti_type == IGMP_V1_ROUTER) { 409 rti->rti_time++; 410 if (rti->rti_time >= IGMP_AGE_THRESHOLD) 411 rti->rti_type = IGMP_V2_ROUTER; 412 } 413 } 414 IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 415 splx(s); 416 } 417 418 static void 419 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 420 { 421 struct mbuf *m; 422 struct igmp *igmp; 423 struct ip *ip; 424 struct ip_moptions imo; 425 426 MGETHDR(m, M_DONTWAIT, MT_HEADER); 427 if (m == NULL) 428 return; 429 430 m->m_pkthdr.rcvif = loif; 431 #ifdef MAC 432 mac_create_mbuf_linklayer(inm->inm_ifp, m); 433 #endif 434 m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 435 MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 436 m->m_data += sizeof(struct ip); 437 m->m_len = IGMP_MINLEN; 438 igmp = mtod(m, struct igmp *); 439 igmp->igmp_type = type; 440 igmp->igmp_code = 0; 441 igmp->igmp_group = inm->inm_addr; 442 igmp->igmp_cksum = 0; 443 igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 444 445 m->m_data -= sizeof(struct ip); 446 m->m_len += sizeof(struct ip); 447 ip = mtod(m, struct ip *); 448 ip->ip_tos = 0; 449 ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 450 ip->ip_off = 0; 451 ip->ip_p = IPPROTO_IGMP; 452 ip->ip_src.s_addr = INADDR_ANY; 453 ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 454 455 imo.imo_multicast_ifp = inm->inm_ifp; 456 imo.imo_multicast_ttl = 1; 457 imo.imo_multicast_vif = -1; 458 /* 459 * Request loopback of the report if we are acting as a multicast 460 * router, so that the process-level routing daemon can hear it. 461 */ 462 imo.imo_multicast_loop = (ip_mrouter != NULL); 463 464 /* 465 * XXX 466 * Do we have to worry about reentrancy here? Don't think so. 467 */ 468 ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 469 470 ++igmpstat.igps_snd_reports; 471 } 472